WASHINGTON — Citing the Maine Republican Party’s highly criticized handling of its presidential straw poll this month, Andrew Ian Dodge has dropped out of the party so he can campaign for U.S. Senate against Sen. Olympia Snowe as an independent.

Dodge said he officially unenrolled from the GOP on Tuesday and plans to gather signatures to try to get on the November ballot.

That leaves Scott D’Amboise of Lisbon Falls as Snowe’s sole GOP primary challenger. D’Amboise and Dodge are aligned with the tea party movement.

Dodge, a freelance writer from Harpswell, said Wednesday that the way the party ran Maine’s nonbinding caucuses convinced him he “won’t get fair treatment in the primary” in June.

Sandy Maisel, a government professor at Colby College in Waterville, said Dodge and D’Amboise were seeking the same conservative voters in trying to unseat Snowe.

“But I believe it is a small share of the GOP vote,” Maisel said. “I still see their campaigns as having no traction.”

Maisel noted that while the state GOP ran the presidential straw poll, the state runs primary elections.

The state party and Chairman Charlie Webster faced sharp criticism after the party had to correct counting errors and omissions from the results announced Feb. 11, and they debated whether to include the results of a postponed caucus in Washington County. The party reported that Mitt Romney beat Ron Paul in Maine, with or without Washington County’s results.

“I don’t think I have a place in the Republican Party in Maine right now,” Dodge said. “I don’t want to support a party that is doing everything it can to disenfranchise people.”

Dodge had yet to file a campaign finance report with the Federal Election Commission, meaning he never crossed the fundraising reporting threshold of $5,000.

D’Amboise, a health care technician and small-business owner, raised $473,465 last year. His campaign spent $338,120 during 2011, much of it on national fundraising appeals to conservatives who regard Snowe as too moderate.

That left D’Amboise with $134,369 as of Dec. 31, according to his campaign finance report.

D’Amboise said Wednesday in a news release that with Dodge’s departure, “we gain a considerable advantage as Republican voters have a clear choice for a conservative alternative to Olympia Snowe.”

Snowe had nearly $3.4 million on hand as of Dec. 31, after raising $629,771 for the fourth quarter. She won re-election in 2006 with 74 percent of the vote, and national analysts don’t have Snowe on their lists of vulnerable Senate incumbents.

There are four candidates in the Democratic Senate primary: Matthew Dunlap of Old Town, a former Maine secretary of state; Jon Hinck, a state representative from Portland; state Sen. Cynthia Dill of Cape Elizabeth; and home builder Benjamin Pollard of Portland.

Jonathan Riskind — 791-6280

jriskind@mainetoday.com

Twitter: MaineTodayDC